Thanks, that's useful to know. Could you have a close look under a magnifying glass and tell me if the capacitors next to the crystal are also missing? I'd probably be able to solder the crystal back on if I needed it, but the capacitors would be impossible.

The only situation where this would be important is if someone needs real-time accuracy in low-power mode (otherwise the RTC can be emulated in software). It would be interesting to see how much power the Due takes with the SAM3X in a very low-power state.

Thanks, that's useful to know. Could you have a close look under a magnifying glass and tell me if the capacitors next to the crystal are also missing? I'd probably be able to solder the crystal back on if I needed it, but the capacitors would be impossible.

I'm still confused. What does the (supposedly official) schematic on the downloads page indicate? RTC xtal or not?

If it is present in the schematic but not on (some) of the boards, what does that mean? Manufacturing goof-ups?

I must admit if plunked down the dough for one of these things at the full official list price, I'd be annoyed if I got one that didn't have the RTC. For $49 + shipping and taxes (and possibly more, depending on where you live) I'd expect something fairly premium, with all the bells and whistles. After all, not exactly cheap for uC dev board, considering the alternatives...

I must admit if plunked down the dough for one of these things at the full official list price, I'd be annoyed if I got one that didn't have the RTC. For $49 + shipping and taxes (and possibly more, depending on where you live) I'd expect something fairly premium, with all the bells and whistles. After all, not exactly cheap for uC dev board, considering the alternatives...

Excactly. I'm dropping this crap, heading in the stm32 direction again instead.

Thanks, that's useful to know. Could you have a close look under a magnifying glass and tell me if the capacitors next to the crystal are also missing? I'd probably be able to solder the crystal back on if I needed it, but the capacitors would be impossible.

I can,

From Arduino Store now Crystal no capacitors.

From eBay Crystal and capacitors.

Thanks again.

I tried soldering on a watch crystal by itself and it is not enough - in fact it is worse, only 42 seconds per minute! With capacitors it runs at a more conventional 60 seconds per minute But there is no easy place to solder the capacitors on (I was literally holding them between the crystal and the shielding of the USB port, which can't have helped the accuracy much).

I tried soldering on a watch crystal by itself and it is not enough - in fact it is worse, only 42 seconds per minute! With capacitors it runs at a more conventional 60 seconds per minute But there is no easy place to solder the capacitors on (I was literally holding them between the crystal and the shielding of the USB port, which can't have helped the accuracy much).

Capacitors are really really important for the Crystal to work proper, they needed that the main frequenz of the Crystal swing. On page 1407 of the full SAM3xa is an formel to choose the right value.

Do we really need to calculate this??? on an product that is randomly shipped with or without crystal?, with or without headers?, with or without labelling on the board?

Wrong question its not the point if you get an board with or without an crystal, if you want an working crystal/RTC with the most possible accuraty you need the right capacitors. So the question is what is the right value. In the schematic the value are 22pF but the Spec says max is 20pF...

Yes right, but if you look at all pictures from the Due on the Arduino pages, the Main or the Product Page, no picture shows an Board with an Crystal on it, so I think more and more the one with an Crystal an anormaly. And older pre Final boards are not relevant for the final release, its an another question why they decided to release them without the Crystal. How Boards without the final marks on the surface are getting to customers is an mystery from the mail-order. May it can solved...

yes, but my board doesn't look like those pictures either.... No jtag heade, no markings on the icsp header, and I have that chip between the headers at rx0 and tx3..And I cannot make that crappy spi to work, so it's like I got some unwanted orphan.